How can I tell if my Auburn is worn out?

[Mastiff]

I've had Auburn LSD's front and rear in my K5 for over 10 years. The things clunk and pop all the time recently. I was going to just throw some more additive in the axles, but I wonder if the clutches are shot? Do they get more noisy when they wear out, or do they just stop working? I used parts store additive last time (a long time ago), so maybe that's part of the issue?

The weird thing is that the front and rear are both noisy, even though the front really has hardly any mileage compared to the front.

 

[folkenheath]

Well if something is broken that's different. But if you just want to see if the clutches are wearing out jack the axle up and leave it in park. Then measure how much torque it takes to slip the clutch by turning one wheel. I don't know about auburn, but for eaton I've heard ~80 ft-lbs or more is fine.

 

[4xcrazy]

I could have sworn i read somewhere, that the additives are really only to help the clutches slip easier, without binding or burning up or something like that.

If you have popping and clunking going on in a limited slip diff, i personally think you have major issues going on in there.

The limited slip i had in a car once never made noises like that, but i knew it was about dead when a few times i tried to "light 'em up" and all that happened was the driveshaft spun, no wheel turning

 

[rufusbooth]

But if you just want to see if the clutches are wearing out jack the axle up and leave it in park. Then measure how much torque it takes to slip the clutch by turning one wheel. I don't know about auburn, but for eaton I've heard ~80 ft-lbs or more is fine.

+1 that is the way to check.

On my stock Eaton in my 12 bolt with the correct additive (GM stuff) it runs nice and quiet. If I dont put in the additive I get clutch chatter. Not shure I would call it a pooping but it certainly makes noise and the truck shutters when going around corners without it.

It cant hurt to run down to your GM dealer to grab a couple bottles of additive and do a quick fluid change front and rear to see if that helps. Besides, while the covers are off you can inspect them for any damage visually.

Cheers,
Rufus

 

[Mastiff]

Resurrecting this because I have the diff cover off now. Anyone know what I should look for? I don't see any clutches really. Maybe there aren't any on on Auburn? Or maybe they are totally gone? I see some shined metal outboard of the side gears that looks like the friction source?

 

[gotblazers]

im not a professional or anything but i took a ford(we didnt have any gm dif's) 9 in rear dif apart and put it back together for a class project and if you have side gear damage wouldnt that indicate bad spider gears? Was there any metal shavings in the fluid? Although the fact that its happending in both differentials at the same time is odd, How many miles on each and what kind of use have you put them through. Just brainstormin

 

[Burbdood 74]

If both of your diffs are popping and clunking, then maybe it's something in your transfer case that's either worn out or binding and the result is that it's trying to engage both diffs. Have you tried to see if they clunk and pop in 4wd?


Just a thought.

 

[Mastiff]

im not a professional or anything but i took a ford(we didnt have any gm dif's) 9 in rear dif apart and put it back together for a class project and if you have side gear damage wouldnt that indicate bad spider gears? Was there any metal shavings in the fluid? Although the fact that its happending in both differentials at the same time is odd, How many miles on each and what kind of use have you put them through. Just brainstormin

The side gears look okay as far as I can tell. There's some sort of thing the side gear is in that is shined a little. If I understand the Auburn right, the friction is at the taper of the side gears, so I'm not sure what's going on.

I'll snap a pic later today.

 

[Hogback Fabrication]

Here's how it works.

 

[chulisohombre]

from what ive seen ,the auburn has a slip clutch that engages with torque.kinda like a detroit but not fully locking.supposed to be only 2/3locking going to the wheel with best grip.from what ive read you should change the oil every 20-30 thousand miles to have clean oil or the clutches wont work correctly.so if its been 10 years id change it and put in 4 onces of the gm additive and see what it does.there should be a clutch pack and spring on either side of the side gears.ive had a worn out one before and it didnt really make noise but took more input to the axle to make it want to move.

 

[Mastiff]

Here are some pics. Is the shiny spot where clutches are supposed to be?

 

[chulisohombre]

im not a paying member so cant see the pics.i also forgot to say,you have to use regular gear oil 89-90 weight.if you use synthetic it will also cause the clutches to slip and not engage peoperly.

 

[frankin5]

Auburn says do not use synthetic gear oil. i made that mistake because a SHOP told me to use it. It made noise like they were about to explode. Put regular gear oil in and quiet as a mouse since.

 

[Mastiff]

Good you said something. I was going to use synthetic. I was thinking maybe I could get away without the additive that way. The additive is expensive and a hassle to get since the dealer is far away.

 

[chulisohombre]

also look at the back of the bottle.some gear oil is already compatible with axles equipped with limited slip diffs.i think i have some in my garage that is compatible,ill have to look.

 

[Hogback Fabrication]

Here are some pics. Is the shiny spot where clutches are supposed to be?

Look at the link I posted before, there are no clutches.

 

[Mastiff]

Look at the link I posted before, there are no clutches.

It says "side gear and cone clutch assembly" in the picture. Am I misunderstanding?

 

[Hogback Fabrication]

It says "side gear and cone clutch assembly" in the picture. Am I misunderstanding?

They do call them clutches I guess but they aren't clutches in the same sense as other posi's.

As for the noise, I'd suspect it is fluid related. Generally posi's just become less and less effective as they wear.

from what ive seen ,the auburn has a slip clutch that engages with torque.kinda like a detroit but not fully locking.supposed to be only 2/3locking going to the wheel with best grip.from what ive read you should change the oil every 20-30 thousand miles to have clean oil or the clutches wont work correctly.so if its been 10 years id change it and put in 4 onces of the gm additive and see what it does.there should be a clutch pack and spring on either side of the side gears.ive had a worn out one before and it didnt really make noise but took more input to the axle to make it want to move.

Posi's don't engage with torque like a mechanical locker and no posi will transfer anything near 2/3 torque to the wheel with more traction.

 

[blaznjon]

use the GM posi additive.Some times it takes two bottles for the Auburn to release properly after a gear oil change.I have Auburns front and back in the 88 blazer.i get the opposite problem with out the additive.My axles stay locked and it`s a plowing squealing tire sliding maneuver into parking lots when the rear won`t release.

Go to the Auburn site and they will tell you that you can scuff the cones and case if you don`t get them to lock.They also give you a release torque for when you have one wheel one the ground and one in the air.to find out if its working properly.

Check there site out it should explain it better then I did.

 

[chulisohombre]

They do call them clutches I guess but they aren't clutches in the same sense as other posi's.

As for the noise, I'd suspect it is fluid related. Generally posi's just become less and less effective as they wear.




Posi's don't engage with torque like a mechanical locker and no posi will transfer anything near 2/3 torque to the wheel with more traction.

if he had the older style posi it has the side clutches and pressure springs to engage the side gears which is less affective than the new style.its been in his rig ten years so i thought thats what he had.torque is what makes a posi work.with the cone style they slide in and out against he side gear as more torque is needed to put power to the wheel that is not spinning.how does that not require torque to engage the posi?i know they dont really transfer that much torque but are supposed to depending on what spring tension you are running in it.you really only get more of a 1/3 bias to the tire with less traction.change the fluid and add the additive and it should run a lot smoother.let us know how it does.if anything the shiny spot if probably where the side gear moves in and out to bias the torque going to the wheels against the adjusting spring.unless you can see something out of place which would prbably be obvious when you pull the diff cover and look inside the case.